Assiqnob to wbstinghoirse



2 swears-swan I G. M. LTTLE. ELECTRIC FURNACE. Fl LED MAR, 23. 192! 46 INVENTOR GeoryefllLllt/e ATTORNEY 2 SHEETS'QHEET 2 Jan. 30, 1923.

Y G. M. LHTLE.

ELECTRIC FURNACE FILED MAR. 23, I92! Hill INVENTOR Geo/"ye M L lZf/e ATTORNEY Patented Jan. 30, 1923- UNITED. STATES PATENT OFFICE.

GEORGE m. mun, or rmsnnnen, rnnnmwmn, nssren'on no wns-rmcnonse nnncrmc a: memo comm, A. conronmxon or rmmvnnm.

mane-mm summon Application Mei! Kare]; 23, 1:21. serial Ho- 417s To allwkonm't ma amwern:

,Be it known t at I Gnome-M. Lrrrmz, :1 citizen of the United .Ietntes, and a resident of Pittsburgh, in the count of Allegheny 5v anclState of Pennsylvania, ave invented a jects to provide a heating element, comprismg a phirality ofunits, and to so mount it,

inn furnace. chamber, out of contact with the furnace walls, as to of maintaining a tern erature of2500f C. or. over, in" each chain qr andjn'which a relatively large j energg in lit "min? be maintained uninterrupte 1y or relatively long periods of time without material damage toany part of the furnace.

Another object of-my invention is to provide resiliently supported compression means for a. refractory sectionalized resistor. Another object of my invention is to provide means, for: water cooling the carbonaceous electrode by .means'of which the current is led into and out of the resistor.

Another object is to provide means for quickly removing a damagedresistor' and mulch; inserting, a new resistor into the tu'rnace chamber. a

' tering rlnother ob'ct is to proricle' a resistor ole-f ment which s allhave a form best adapted to withstand the oxidizing effect of air enprovide means for protecting not nnlythose portions of the resistor which are most suh- 'jecl. to the oxidizing influence of the entering air but also the furnace walls.

Another ohject of my invention is to pro vide an electric resistor furnare in which the: 4

tll'lglli to dropfupon a heated; refractory memupper portion of the furnace chamber. in which the heating element is located, shall al ays be filled with hydro-carbon vapors,

. while the lower ortion of the chamber may or may 'not he lied therewith, as may be desired. As the metal to be heated is to be placed in the lower portion of the furnace chamber, it may be heated in either an oxi-q (lazing n n re lum ng atmosphere.

'stand the relatively ,hig

the furnace chember nnd further to.

' Another object is to provide a roof made of carbonaceous material in order to within temperature experlencecl in the operation ofth furnace at temperatures of 2509" .C n'nd over and to protect the same, by the hydifoarbon' vaors, geinst theoxidizing notion of inleak- 1n en.

; nothe'r object of m .mventibri is to provide a reletivelyeimp e nans'jor varying the resistance and, therefore,' the; current inp'ntinto a accordance with aha d i edmp y b ef wi iee I another ob ect of nyfinvention is to 1glrowde 'e lreeilientlmoonting for the entire mace so'arrantfie e l e t sn p refractory unmanned e'ncl nfiuriiaee chamber. J I p rofitle'a resistor 10- cetecl in the uppeFpart cemented at a substantial distance 'tlie wall's',*said resistor comgrisingfa' m -slayer separate elemonts ,'an Lingerie or'iioiiip'i" I tl eee elements, said' .eoin 'r'essin""1ne1ins Being resilientandfadjusta 1e. Pror'rideiosilint suspendin m n's fo'r'theT ht'ii erilis dfithe terminal 3 eetrodes whicli'e:ttend' through "on'e 'of the wiser the 'cliaiiiherfind mount a water-cooled ter'minaPat ithfjhd 'of' the electrode. "I proyide, further; a substantie lly statioh'aryfivater hoole'd i'net'al" collar located" in the' dl'ltcr art of'the' w'nll for further cooling said ectrode.

I; provide mezi'riii'fu creating, hydrocarhon vapor in the furnace ch'ambei' coin prising a reeeptacle for oil and means fbr introducing s'ind oil'intoth'e chamber-and'for permit her located below said resistor" and so arranged as to reflectthe dI'QPS'Of'OIlitgflll-It the under surface of said v I proYide" f'esi'stor elmentsf'made "of a carbon'aceous niaterial', which the center offgravit of the lnteral "area" of crosesection is be ow" the center line of compression, and I further prdi'ideimeiins for restricting dos jto'po-operatolwith the the contact area of adjacent elements to an area. relatively less than the lateral area of cross-section of the element itself.

In the accompanying drawings:

5 F e 1 is a'view, in horizontal cmss seze tion', on the line I''I of Fig. 2,01? mfumace embodying my invention;

-- Eig; '2: isra view, in pyerticel oross;sectin,

on the line 1'I.:I-I of '1 mf the :furnaoe; Fi n 3 is a view, in lateral ores-section, on the line HIIII of Fig. 2;

Fig". 4 is a view, in front elevation, or the resilient suspending inefihs forlm Welter" icooled terminal andthe outer end of the lielectrode;

f5 'and V6 aremewsgxnrront elBVIt LlOIr zrn cl infjseotion of a resistor e'le-' -ments ofthe work to.be.done'in,tl 1e .furnace The refmctoLy'linings ofthe furnacehre so nrrungedns to provide; furnace chamber which may beof any desired coutonrlmt is here shown as substuut-ially recmngular in form. Intheupper part of ,the ehuinher 6. I mount it heatingelemeutfrwhieh-ishere shown nsmoomprising :two sets of earbonaceous resistor element's-to .be hereinafter described in detail. .Iheheetinmolemenls 7 are shown resilientlyeon 1: -hy-mean5 of aspring-pressedeleetr e8, substantially circular in -cross1 seetion and extending through one pfthe furnace wullssuhstnn- Aiully as iudicatediuF-igs. .1 and 2. .1 pro- .vide {ll graphite buel; plate .9 against which one .end of-euch .oLthe resistors [7 maybe placed. and Lpmuidoia ieglite plate 10ml. lhefrout end ofi aach-ol 'rtingaleuients which .l$;SL:lgllt l\yihUllOWd out imits outer face to ueee re, HLQduQ rate with, rthe rou nded linnorond. of the eetrode 8.

A metallic lllBlHlJQIE-li ,oisubstantiallyu shape is (secured to the {metallic casing '2 ,to.;prov,ide asmoanssto cooperate with a spring-l2, -11 spaeingrimemberelll axthneaded rod 14, a nut 15, and a asher 16 to resil- ,Iermit of wotenor other ooohng fluid land in end e1evntion,'-respepti\ ely, of a, modiently aress against the outer end of the electron: 8 and thereby maintain the eleofrode S, erlid plates 9 and 10,a.ud the built-up renting e ement 7 in r0 1' 0 tive osi- :tions. The threaded l 'hd' l l mm pei inib' ted to project through the mom 1- '11 in order to maintain it in substantial alinement with the :electrode, and auitable nlay -.be -prov1dod tom-5111MB this rod-either from the member 11 or from the outer end of the electrode 8, so that a proper current ath may be provided through the resistors lilassive-contaot terminals 17 are provided on each of the electrodes 8, and provision is n ade for water-(roofing thefseme, the said provision comprising: tube 18 to conduct .the .ir tor to and from the'termmals '17 which are suitehjly ooredmut to therethrough.

L4. 'member 1s seeured to the member 11, and at 19, of substantially Usshape, c P ember 20 .lspro ded S $Pnded ,firom the fw w ilmd it y 11 th wat r i entl fienp the cooled terminal 17 to i ti a s u e 1. ntifll som- 'ii s n-th r e edepr r d o wwiber 20 jto 'pei'n iitflfproperly the LPP n fi t s membe en fi s elegrode 18 ,to which the member fl'l'is seouned, so'thet be emitte'd to move freey ,mt o ope ing lut euwfl o 'lih naoe.

Quring qthe operation of the futnaoe,

shrinloggemay ooenr injthe iurnaoo wells or in the resistor members 7 which make it nec- .essury-cthat the electrode 8 he pmnitted t'o ,Inovejfrcely'to follow such shrinkgge or rel- .git ve movement of the wallsand the resistor.

i As the tem erature .which may be at tained in the furnuoe chiunber 6 isreletively high, (-2500 C. or even higher) it mayihs ppen thattheloctrode 8 become hosted to a relatively high temperature andfin order to, .protect the-sumo and "to reduce .the temperature ofthe samecahthe outer wall of the .Iurnace, anuuxilie-ry ,cooling comprising a substantiallystatlone ex, is .loca'tod at the outer surface of t e mallto surround .the electrode 8, with a relatively small -cle urance ispace :therehetnteen. The memheuQ-i may .be suitzrh ooredzso that vwater woling may ,he einp' oyed,.this-coolin Ming in addition tothatjllieto the Ava- :20

tercooled terminal members 17.

'l'heheating element .7. comprises a plurat .ity ufsubstsutmllyflatplates .of when ceous nnterial of a [form ,to

set forth indetaihiandI-heve nsedplntsof 'ca rhon xv itln exeellerttmesults Vh ilelI hame illustrated a tworpart heatinguelemenhlidonot desire to healimib d thereto, asl ,maviiseonlyone ofth resistor members 7 and locate the terminal lectrodes at o posite'sides of the furnace and of the singl resistor. i

Inasmuch as it is desired toproyide an electricresistance furnace for heating metal objects an opening, indicated dia mati y at 24 in F 1 and 2 is provided the lo'wei' -part'o sheen herthrou h 'which the metal objects to be heated may e introduced. This opening;- of course, permits air to'enter a'n'd' as this entering air containsoxy'gcn, it will-affect the heated resistor and cause theaifectedj'snrfaces to oxi dize and wasteaway.; In "orderjoj reduce the effect of this oxid1zation,f'1':'provid e resistor elements, the'vertlcal dimension of which is greater thanthe horizontal 'dimen sion, and I further so arrange the relative location of the resistor elements and oithe electrode 8 as to bring tha'eenter line of compression well above the center of gravity 'of the lateral area of the resistor elements.

In 'order'to obtain the proper contact area which, in general, determines the resistance to the flow of cirrrent'through oh's of'the one surface of each 'element to' 'rediic e' the contact area, orl'n' ay'provide alternate ele- 'ments'of relatively smalleross-se'ction, in order to' reduce the am; ofcmitact through which the heatixi cllirent flows.

' inerit 1compri'sing, gen'ralfa memberf25 30 of substantially X-shape similar to that in silbstantlally- X-form; the crossingi "of thetwo parlsbeing-substantlall t u ter li'ri'e of dimension of the" assembled remensi'om Integral- 'riise'd "portiohs" 6 are ro lided on] one surface of the of relatively small area, and fare; arrange e cen- Figs. 7 and S indicate another form of re-' sist'or element and comprise a substantiallyflatnemb'er m of rectangulararea; on; one" 'siirface of which aretivo spacednliichp'afileh raised;portions 28exten'd1ng on'e to a pomtalittle beyondthecenterof 'area. of the member 27.

Figs; 9 jand 10 indicate-smuanother tom 'of resistor elementfcomprising'a substantially rectangular fiat plate '29, zone surface of which is provided witha' raised portion of thin substantially rectangular platesfil alternating with thin and"relative1y small sistor and quickly inserting sistor member 7 and'may'be arrahcged' to be of the furnace'and'a'suitahy sha dbstantial ly trapezoidal areafth'f lower the type"? 34 I hf the 7; theinit 15 may be operative'lo'cation 'ivithregard to the rectangular plates 32, the lower edge of the plates 31 extending substantially below the lower edge of the lates 32.

In order to permit of varying the current input into any' 'ven'siz'e of furnace and with a substanti y constant voltage of the supply circuit, Ijvary the area of contact between the suocessivecle'ments of the heating member 7, increasing, for instance, the area of the raised portions 26, 28 or 30, respectively or the area of the alternate sections 32. n general, the greater the area, the less ,is the resistance ofthe built-u resistor 7 and, therefore, the higher will the temperature obtained in the furnace chamber 6 for a given voltage.

In order to provide a relatively simple means for quickly removing a damaged rea new resistor, I provide a removable 's'eet on in one 0f the walls of the furnace, removable section being indicated in general, 38 in Fig. 1.

This removable section is located substantially opposite to, and' laterailly of, the reremoved ae'almitf'or the'indivi s1 portions of the walls;3,' '4 and}? ma beremoved separately, a'smayfbefoiind z'h'dst convenient. In case the resistor member 7 should become damaged to such a'nbxtent 'as tdrequire re mm thewalll's'e'ction '83 maybe removed in'ot iding a .suitahlii" arm the wall or handled tray {nay be'zntr'odude throug 'andsoheld as to support one backed'ofi' sufficiently to permitof withdrawing the 'eIectrode'B and this permit of repoint moving the resistor member 7 a unit, lab erally and outxyardly throu h theopening 34. A new resistdrmeihber may be built up of the ro er niirhl'ier of elements 25, 27,

29hr 31 an 32,;theelements1being temporanly gluedtogetlierby means of a suitable bm clel", such as glue, "itch; o'r fluid tar *1 10 {6f m a ha up er e Itli my? and introduced into thefurhace'chamber through the openingM'untfl it is in substantially ite back plate'9, ater:which the not heagainturnedon thest'ud 14 folce the electrode 8 against the resistor member 7 and properly compre the same. a

As hereinbefo're stated, a certain amount of air'entersfthrough'the o ening 24 and 1:0 causesoxidatio'n of those su ces of theresistor member 7 with which it comes in contact, and, in orderto reducethis oxidation, l provide means for creating a sooty vapor l1'1-l3ll8 furnace chamber adjacentto those surfaces'of the resistor which are-most afiected by the oxidizingaction of the incoming air. A container 35' mounted at :the top of the furnace in which may be placed oil, which is permitted to drop" into a receiving, tube 36 pols .will strike not only the lower surleu-o of the resistor members 7 :but also theamlls .of the .furnwe so that all cracks or 01mm 'be sealed .in a. relatively short ,lmvlngA retuxn he l d. The ltmur and -u[' {the tube 36 .pro'ects into ihlgilfmlfy ,tube 37 of relatively s,1: .diameteltand thisper- .mitstherqlzqps-of o .to iflll-i mihe furnace I 5 .ohamber 31110.11. :1

mi emgeq e m m re fie eb em r iQ y-m mb p .ed .,tq l .witbsta.nd the high t e,m peroure to h h t-is .su ieq d- A-s indicated In e- 2 the-m ember.38 maytbogartof e-ren ovable qwallesectionfill, sogthat jump. .beleagily and .qu'i&y lemoved gmd .cleeoe if it becomes ,too deeply .eoverodwith soot to perform ropenly and efficiently its .desirediurmtion.

he drops (IE-oil trove the tube;37 will fallupon, and .be reflect from, lheupper surface of the projectilg ledgefifigthus beipgxlefiecmd against-the. lower eux'face of 'theresistgr members; Afepthe mmnerg ore .qfa he refimtqw h is,$nb mtw+l1y that: oft-(the mis er member-.2, ,thg pf oil M611 4126 rolatil-igze d-landfiqmckedfl Limmz mly pe kin -eke Edge, -1 th EQ -LlUIfl Hl t.ime.' and become ;practically air-tight. In order to provide means for permitting any |.e xoess of s oqty vapor to escape, an opening 14 1s provided in the lower part of the 1-.chamberoud is .connected to a suitable remox mble box secured to the outside of th e wallin nwhieh' is providecle suitable ;op'e1fin g' through lwhich any excess of sooty .yqggr may 'flowinto the atmosphere.

La I'urneoe of thistype may be installed -,l,in,;a;. lgqation s vbc sre it .will be subjected to szj bglitl'qn, reesonof a steam-hammer qgemtedy to work on the materials 1 .by theeaid furnace, I provide a re- .s l ent means for the entire fur- A .plu 't vvofeupport' members $lqfl-y ,plaoe on .a'plo'ogier. oundation into which Rfoject thread rods 7,1surnne suitable helical v srri'iigs :Sllit- ,inh'ybQadjusted .by .means 0 'ec'tlto vibration, it may cause m .7." min 11 tends to memoir Wfefsub i age-251:. g? eznnts ,to 511 and fall and 418,668 ereJmown, mnwhiel e .neutralwzptn osfig e nml hees it s, 30.

f he r, mem h tme eswt nce o'i i -m em md 1wi P9ie that tlie method herdgiseloseglrowicieswhat e to .t e electrodes 8, I v isable to make the filgaifilioohbefwoen .the .eleqtrode 8 and' the wells surronndi .the opening 22 and beousetidm ymay .he .termecl;en lffieoergtiye. ,a gpogpbere wqemthplpo r e 8 and the collar 23 as 418-1 hliwefoundtbat notggly jg oxidat onof gthe'qsurfaces qbthe msrstor t viellig g h lylp mfls ntm q mi -e n ens-as REWP WWLQW M SJfl K-l eeee yietm n w ,able bothuildrug t .comefeoxered with-Jo soot. -t- -6 PQ51b'WhlGh moy'eventliallv hardemand eoome.a part of :the resistor elemeotitself. l

The top \of the rfucnsme .oomprises a. sepaliat metellioeasiug 40 ,to iacihtate its-quick removal from thetop :of the :fumaewshpuld this become necessary. An ,inner wall ,cog irises suitable -he,at-res i tin Jrefmctory ticks A1 nzhich may. be. fire riclrs ,or, :i desimd, -01 c arborund um .slabs ppblocka {Chis wall is sonrmggedas to leave.a substaotiall opemspooe 4-2 .in which .isuplaoecl a plurality -of.-c.arbon bricks .or.,slnbs 43.

The space between the.tgp of-. the slabs 43 and the top of,th.cas' Q0 maybe filled with finely divided .grerfigr material. which may comprise cparselypowdemd coke uext tovtlieslabs $3 and more e lydiuidedpmvrlered coke atthe topoft o i0.tl\e general idea being to provide not only a. heat-resisting covering .for the top .of .the furnace, but also awself-sealipg porous ooyen ing 'in which the openiogsbeoozpe re idly choked by the sooty vatpqrslcreatecl, as eretofore described, so as toseelthetQp of the furnace practically-alright. In this connection, it may be noted that the sooty vegalen ents sub- 1 {.tlrexelliont "compreesion means in combif .Jmtmnw1th1the resilientlsuspending means,

' ,m mber ,17 mounted thereon.

t rminal a I QAs-Jhereinbefore set forth, .a. oertain ,em'ount-of ;mo1zement .of the electrode, relative -to the .xwll'throx h which it projects, .ivill occur by reason 0 the shrinkageof the p'ells aftereontiuued operation of the furl eee egdelso by .reason of shrinkage and ,qxgapsmn of tho.1'esistor members I, uml

:will ,permitsuch-relative movement of the eotrodes as may be required.

The centerline of compression of the re- ,s istor members .7 is loouted avell above the fcenter of gra.vity of the lateral areaof the jndividualelements for the reason that, if V no means for. creatin" u sooty vapor in l .the chamber should failto operate properly 1 be disconnected :by the operator oxidati onpf ,the lower surface of the resistor would take plzice rapidly. with a resultant :wemin fiwa ypf the lower purt of the area ofthelludiiudualelements and iflhis were coutinuer'l "for any substantial length of time, it mggbt lmppen that the entire resist- 81169,!Ii9fi1 er] would tend to buckle in an upward direction, a tendency which is de leyod to aoo isidereble extent by the adopof the resisto s'mndeis 6' air.

see w tion of the formshereinbefore described-11nd,.-

.selves. -Besilientsupportingi'means electrodes supported entirely at its ends by compf'egl? .m-u md-bacminimna tirely prevented if the .-generation=of-sooty and,=.accretive .-zvapors iaymaintained. ,at all idurin themperaticn at ez ur c 1 o It may-=be;-neted-.-fl at;fli e: devices'embodya ing my invention; provides. =-res1lient,-,sus pendi means;iorsthemuter endarof-sthe r: electro es;which permitsgofzirieewmovementfi ofthe? electrodes. and substantiallyecepstante compression of the resistor elementsfthetzlills's entire :furnace .-is -:prov1ded;-iwhic'h rcoogelrs; ates-with the resilient electrod. gq means to preventsb doiithei. ccti ode' when theiumaco-i i J tovibratiop ze "The device embodyinglmyliniintioriroe. vides cooling means for ;the buteneiid-o the: terminalrelectrode nand :zidditional cdolin'g means zfomanuintermediatesiporfiiom lot" the I EThe 'resistanceielemenn useoznmone nemcew embodying'myinaentionismlatil'ely' his and: inherent! meansufonrediming-thelo fiect of'l incoming-air; thnsrmsmnghardlatively long m mm"? ditions.ae'I5iessmhe1inherent-rueamralsb permits;oflocating.thrcedterglinefbflcomprese sio'n of.-the-resistor-aboire:the centenrof grav i ;roflthetlelheutpthnsybndingflbliaplbynt; 2 T f I! n bmliens I IlcGaSBB the lower ortion offirthe'xelements-u. is reduced by oxidation. Thefrresistbr inemlo ber; maintained ixfaoperhtiwposifioh ehtirelyl fi'eefroimitlie siirrounding -wi'aillsian'd v sionlinbilis fr'l The device embod ing my invention rovides a roof for a ace chamber w 'ch is non-lieat-conducting and which cooperates with means inside the chamber to seal itself against the passage therethrough of The device embodying my invention provides relatively simple means for permitting the removal of a damaged resistor member and the insertion of a new resistor member without dismantling the entire top of the furnace.

The device embodying my invention provides a. relatively sim 1e means for creating an accretive atmosp ere in the furnace chamber in which a resistor member comprising a plurality of carbonaceous elements is used, which vapors will, to a great extent, rotect the resistor elements against the oxi 'zing action of entering air.

The device embodying my invention provides relatively simple means for .varymg the resistance of the resistor member in accordance with the desired kilowatt capacity of the furnace and, hence, permits of obtaining any desired predetermined temperature in the furnace chamber conditionslof To ration.

*Various modifications may be made in the device embodying my invention without depa v ironrthe s irit and scope thereof, andIi esirethaton y such limitations shall bev'placed-thereon asare imposed by the prior art or are s ecifically set forth in the appended:claims.-

1. claim as my'rinventionz- 'flm'A-Xl: electric-resistance furnace comprisingi'a -carbon-plate resistor, carbonaceous terunder given.

mmals'plate's therefor, -.carbonaceons elec-' trodes, engaging said terminal plates and coo' means surrounding-the outer .cnds ots'ai .In ranv-clectmc-reslstance- Iurnace; tne ooinbina'iiom with' .a chamber, av resistor in saidchamber-hand arhonaccous terminal plates opcratively :ongagingsaid resistor; of elongated; terminal electrodes-' engngingfsaidz-terminal platesa resilient suspendmg means for the ontericnds of said clectrodeszn '13.? Insmeleetrodewesistance furnace, the

combinationvlwith a chamber, and i a' resis tomlocatod said; chamber, of" elongated termiiiali-xelectrodes operatively "'e'ngagi said resistomand exten ing outside the wh fi ofwsaid srchamberg ecombined contact -terniinalswand'ieoo' .smeans en electrodesmnd has ient fOL'I'iSSid." cb'ntact? :termin'als' 'and' cooling nie'ans.

conibinatiomiwitli fufurnace chamber, and terminal ielectrodes. opcratively "engag' Said resistomand projecting through ai'wail' of said furnace, of combined contact terminals and cooling means secured to the outer ends of said electrodes and a stationary cooling means surrounding said electrodes and located intermediate said resistor and said terminals.

5. In an electric-resistance furnace, the combination with a chamber, of a resistor in said chamber comprisin a plurality of elements d' sed face to ace in a direct line between thg terminals, and means to comress said elements, the line of compression ing located above the center of gravity of said plates.

6. In an electric-resistance furnace, the combination with resilient com ression terminals, of a resistor operative y eng g said terminals and comprising a. plu ity of elements disposed in a direct line between said terminals, the larger portion of the area of each element being located substantially below the center line of compression.

7. In an electric-resistance furnace, the combination with a casing enclosing a furnace chamber and having an opening in one of its Walls, :1 carbonaceous sectionalized re- 0 eratively mi a s saidl suspending 1 means ofits walls adjacent the-upper par sister in said chamber, an elongated electrode operatively engagingssid resistor andprojecting: throu 'h a well ofi said casing: and movable relatiuel iy tosaid wall, and resilient compression means for said electrode and said: resistor of adjustable and. resilient means-for. facilitating the movementof. said electroderinz said wall:

8. An electric furnace comprisin 'ascasing enclosing a furnace chamberan lizw-ing an opening therethrough at the: lower part of said chamber,.a.nd: a carbonaoeousresistor. located in the upper part of said chamber" and having. integrall means for reducingeoxi dation of! the resistor.. V i

9. In an electric furnace, the combination with acasing enclosing a-funnacel chamber said oasiug havin p an opening therefihmugh at-thc lower part, ofsaid chamher offacar'- honaeeous resistor located in die-upper pactof said chamber and comprising a phwality of elements in contact waiilxeaclh other"; and embodying: IDBBJIS-J'OIL said elements; :fon reducing oxidation of the contact surfaces.

10. In an .el-ectnic-resistancerfunnacoi the combination with a housing euolosiiigeu fiurnace chamber and haviugja-n openin%.:imone ioffldie chamber,- a. carbonaceous sectionehz'edi bee sister in said chamberlam elong'ated'elec-- t-rode operatively eugagingr'saidi rsistor and: projecting: through saadi wall opening; andremovable relatively to-rsaidt wall; a contact: terminal secured to the outer end ofi-said; electrode and resilient. compression means for said electrode and saidnesistor, ofi'nesilient suspensidmsecured to said contact terminaL and. msilienhsupporting'means for said furnace housing co-operating with said resilient suspension meansforpermitting saidwapor'to strike the lower surface-0f: saidresistor; located. in. the ug ier pant nfl said.

chamber; means for. intro using: oil intothe upper part of said. chamber; and means-lorawrl in saidrchamber below said: resistor for receiving and vaporizingsaid nilr 13. In win-electric furnace, the combinatiom with: in housing: open' at the topand: ou-' closing a furnace chamber, a carbonaceous resistor looatedi insthe; upper pert of said chamber; of meansfor generating? sootiy vapors in said chamber, and a..;covering; fior the; top, ',or"- sel-idchirmber. comprisingmaterizrlz which snonvheat conducting aud'selfi-sea'h ing againsh said sooty vapors;

14:. fimlelactvio-resistsincafurnaca compnisf ing; ,an: enclosing chamber, hydro-carbon.

vapors therein,-. a.- curbom-plate; resistor in said! chamber, carbonaceous el'ecbrodes; opemtiivelyz engagingrsaidrtemninelnplates; and contactnterminels secured ofzsaidaeleelzmdes.

In testimony whereofil I have hereunto subserilied'rmy-name-this b5tihide'y. of- March, 1925.1: :I I

GEORGE M. LLBDLEJ.

tothe outer endl 

